"There is still considerable volatility in global dairy markets," said Mr Wilson.
"Right now we are seeing a number of factors that are delaying a sustained return to higher global prices."
The global milk supply remains greater than demand, which has resulted in GlobalDairyTrade prices for Whole Milk Powder falling 16.9 per cent since late September, while Skim Milk Powder prices have fallen 7.7 per cent.
"Falling oil prices, geopolitical uncertainty in Russia and Ukraine, and subdued demand from China as it continues to work through inventory are all contributing to ongoing volatility and weak demand," Mr Wilson said.
"Today’s revised forecast reflects the Board and management’s best estimates at this time. Given the uncertainty we are advising farmers to continue to be cautious with budgeting and we will update them as the season progresses."
Chief Executive Theo Spierings said Fonterra was undertaking a targeted programme to generate more cash to support farmers.
"Cash is important for our farmers and for our Co-operative," Mr Spierings said. "We will be further strengthening our tight controls on operating expenditure, and will be driving harder on working capital, and deferring capex – provided this does not slow progress on our V3 business strategy.
"This is a clear signal to farmers that we are all in this together. We are tightening our belts, just as they are."
The Board expects to look at the estimated dividend range at the time it announces its Interim Result.
Fonterra is required to consider its forecast Farmgate Milk Price every quarter as a condition of the Dairy Industry Restructuring Act (DIRA).